Effect of fatigue on explosive strength and muscle architecture of the vastus lateralis / Efecto de la fatiga sobre la fuerza explosiva y la arquitectura muscular del vasto lateral / Efeito da fadiga na força explosiva e arquitetura muscular do vasto lateral

ABSTRACT Introduction: There has been little research on changes in rate of torque development (RTD) and muscle architecture. This study evaluated the effect of fatigue on RTD and muscle architecture of the vastus lateralis (VL). Methods: Seventeen volunteers (25.5 ± 6.2 years; 177.2 ± 12.9 cm; 76.4 ± 13.1 kg) underwent isokinetic knee extension assessment at 30°/s to obtain the peak torque (PT-ISK), before and after a set of intermittent maximal voluntary isometric contractions (MVIC) (15 reps - 3 s contraction, 3 s rest) used to promote muscle fatigue, monitored by the median frequency (MDF) of the electromyography from the VL, rectus femoris and vastus medialis muscles. Before and after the fatigue protocol, ultrasound images of the VL were obtained to measure muscle thickness (MT), fascicle length (FL), and fascicle angle (FA). The peak isometric torque (PT-ISM) and the RTDs in 50 ms windows were calculated for each MVIC. The RTDs were reported as absolute values and normalized by the PT-ISM. Results: Fatigue was confirmed due to significant reductions in MDF in all three muscles. After the fatigue protocol, the PT-ISK was reduced from 239.0±47.91 to 177.3±34.96 Nm, and the PT-MVIC was reduced from 269.5±45.63 to 220.49±46.94 Nm. All the RTD absolute values presented significant change after the fatigue protocol. However, the normalized RTD did not demonstrate any significant differences. No significant differences were found in the muscle architecture of the VL. Conclusions: The reduction in explosive strength occurred concomitantly with the reduction in maximum strength, as evidenced by the lack of changes in normalized TDT. Level of Evidence III.

RESUMEN Introducción: Los cambios en la tasa de desarrollo del torque (TDT) y la arquitectura muscular causada por la fatiga son temas poco investigados. Esta investigación evaluó el efecto de la fatiga en la TDT y la arquitectura muscular del vasto lateral (VL). Métodos: 17 voluntarios (25.5 ± 6.2 años; 177.2 ± 12.9 cm; 76.4 ± 13.1 kg) se sometieron a una evaluación isocinética de la extensión de la rodilla a 30º/s para obtener el pico de torque (PT-ISK), antes y después de una serie de contracciones voluntarias máximas intermitentes (CVIM) (15 repeticiones - contracción 3 s, intervalo 3 s) utilizadas para causar fatiga muscular, monitoreadas por la frecuencia media (FMD) de la electromiografía VL, recto femoral y vasta medial. Antes y después del protocolo de fatiga, se obtuvieron imágenes de ultrasonido VL para medir el grosor muscular, la longitud del fascículo y el ángulo del fascículo. Se calculó el par isométrico máximo (PT-ISM) y las TDT en ventanas de 50 ms para cada CVIM. Las DTT se calcularon en valores absolutos y se normalizaron mediante PT-ISM. Resultados: la fatiga se confirmó por reducciones significativas en la fiebre aftosa de los tres músculos. Después de la fatiga, el PT-ISK se redujo de 239.0 ± 47.91 a 177.3 ± 34.96 Nm, y el PT-CVIM de 269.5 ± 45.63 a 220.49 ± 46.94 Nm. Todos los valores absolutos de TDT fueron significativamente diferentes después del protocolo de fatiga. Sin embargo, las TDT normalizadas no mostraron diferencias significativas. No se observaron diferencias significativas en la arquitectura muscular de la LV. Conclusiones: La reducción en la capacidad explosiva ocurrió simultáneamente con la reducción en la fuerza máxima, evidenciada por la falta de cambios en la TDT normalizada. Nível de evidencia III.

RESUMO Introdução: Alterações na taxa de desenvolvimento de torque (TDT) e arquitetura muscular causadas pela fadiga são temas pouco investigados. Esta pesquisa avaliou o efeito da fadiga na TDT e arquitetura muscular do vasto lateral (VL). Métodos: Dezessete voluntários (25,5 ± 6,2 anos; 177,2 ± 12,9 cm; 76,4 ± 13,1 kg) realizaram avaliação isocinética de extensão do joelho em 30º/s para obtenção do pico de torque (PT-ISK) antes e após uma série de contrações voluntárias isométricas máximas (CVIM) intermitentes (15 reps - 3 s contração, 3 s intervalo) utilizadas para causar fadiga muscular, monitoradas pela frequência mediana (FMD) da eletromiografia do VL, reto femoral e vasto medial. Antes e após o protocolo de fadiga, imagens de ultrassonografia do VL foram obtidas para mensuração da espessura muscular, comprimento de fascículo e ângulo do fascículo. O pico de torque isométrico (PT-ISM) e TDTs em janelas de 50 ms foram calculados para cada CVIM. As TDTs foram calculadas em valores absolutos e normalizadas pelo PT-ISM. Resultados: A fadiga foi confirmada devido a reduções significativas da FMD dos três músculos. Após a fadiga, o PT-ISK foi reduzido de 239,0 ± 47,91 para 177,3 ± 34,96 Nm, e o PT-CVIM de 269,5 ± 45,63 para 220,49 ± 46,94 Nm. Todos os valores de TDT absolutos apresentaram-se significativamente diferentes após o protocolo de fadiga. Contudo, as TDTs normalizadas não demonstraram diferença significativa. Não foram observadas diferenças significativas na arquitetura muscular do VL. Conclusões: A redução da capacidade explosiva ocorreu de maneira concomitante com a redução da força máxima evidenciada pela falta de alterações na TDT normalizada. Nível de Evidência III.

Body composition, strength static and isokinetic, and bone health: comparative study between active adults and amateur soccer players / Composição corporal, força estática e isocinética, e saúde óssea: estudo comparativo entre adultos ativos e futebolistas amadores

ABSTRACT Objective: To compare tissue composition, total and regional bone mineral content and bone mineral density, static hand grip and knee joint isokinetic strength between amateur soccer players and Control Group. Methods: Cross-sectional study. Air displacement plethysmography was used to estimate body volume and, in turn, density. Body composition, bone mineral content and bone mineral density were assessed for the whole body and at standardized regions using dual energy X-ray absorptiometry. Static grip strength was assessed with an adjustable dynamometer, and peak torque derived from isokinetic strength dynamometer (concentric muscular knee actions at 60°/s). Magnitude of the differences between groups was examined using d-Cohen. Results: Compared to healthy active adults, soccer players showed larger values of whole body bone mineral content (+651g; d=1.60; p<0.01). In addition, differences between groups were large for whole body bone mineral density (d=1.20 to 1.90; p<0.01): lumbar spine, i.e. L1-L4 (+19.4%), upper limbs (+8.6%) and lower limbs (+16.8%). Soccer players attained larger mean values in strength test given by static hand grip protocol (+5.6kg, d=0.99; p<0.01). Conclusion: Soccer adequately regulates body composition and is associated better bone health parameters (bone mineral content and density at whole-body and at particular sites exposed to mechanical loadings).

RESUMO Objetivo: Comparar a composição de tecidos, o conteúdo mineral ósseo e a densidade mineral óssea totais e por regiões do corpo, a força de preensão manual estática, e força isocinética da articulação do joelho, entre um grupo de jogadores de futebol amadores e um Grupo Controle. Métodos: Estudo transversal utilizando pletismografia de ar deslocado para estimar o volume corporal, para subsequente cálculo da densidade corporal. A composição de tecidos, o conteúdo mineral ósseo e a densidade mineral óssea foram avaliados para o corpo todo e regiões padronizadas através da absorciometria de raios-X de dupla energia. A força de preensão manual estática foi avaliada por um dinamômetro ajustável. Os momentos máximos de força das ações musculares concêntricas para os extensores e flexores do joelho foram avaliados pela dinamometria isocinética (60°/s). Foi calculado o valor d-Cohen para apreciar a magnitude do efeito das diferenças entre grupos. Resultados: Os futebolistas apresentaram níveis superiores de conteúdo mineral ósseo em comparação com os adultos ativos do Grupo Controle (+651g; d=1,60; p<0,01) e obtiveram valores superiores de densidade mineral óssea (d: 1,20 a 1,90; p<0,01) para a coluna lombar, L1-L4 (+19,4%), membros superiores (+8,6%) e membros inferiores (+16,8%). Para a força de preensão (estática) a diferença foi moderada (d=0,99; p<0,01) com valores mais elevados apresentados pelo futebolistas (+5,6kg; d=0,99; p<0,01). Conclusão: A prática de futebol promove uma regulação adequada da composição corporal (tecidos magro e gordo) e ganhos na densidade mineral óssea, mais acentuada em partes do corpo com maior exposição aos impactos mecânicos da atividade motora.

Desequilíbrio muscular dos flexores e extensores do joelho associado ao surgimento de lesão musculoesquelética relacionada à corrida: um estudo de coorte prospectivo / Muscle imbalance of flexors and extensors of the knee associated with running-related musculoskeletal injury: a prospective cohort study / Desequilibrio muscular de los flexores y extensores de la rodilla asociado con lesiones musculoesqueléticas en la carrera: un estudio de cohortes prospectivo

Resumo O objetivo deste estudo foi verificar se o desequilíbrio dos músculos do joelho pode estar associado com o surgimento de lesões em corredores. Vinte corredores fizeram uma avaliação isocinética nas velocidades de 60, 180 e 300o/s e foram acompanhados por três meses para verificar a ocorrência de lesões. Quatro atletas (21%) apresentaram lesões que envolveram a região do joelho e o desequilíbrio muscular encontrado foi associado ao surgimento de lesões, nas três velocidades testadas (p < 0,05).

Abstract The aim of this study was to determine whether a muscle imbalance of the knee is associated with running injuries. Twenty runners were evaluated by an isokinetic dynamometer at 60, 180 and 300 degrees/second. Runners were followed for three months to determine the incidence of injuries. We used the chi-square test to verify the association between muscular imbalance and the appearance of injury. Four athletes experienced injuries (21%), all registered in the knee. Muscle imbalance was associated with running-related injuries for the three tested velocities (p < 0.05). To conclude, a muscle imbalance may be associated with running injuries.

Resumen El objetivo de este estudio fue determinar si el desequilibrio muscular de los músculos de la rodilla puede estar asociado con la aparición de lesiones en corredores. Veinte corredores realizaron una evaluación isocinética a velocidades de 60, 180 y 300º/s. Se hizo un seguimiento de los participantes durante tres meses para determinar la incidencia de las lesiones. Se utilizó la prueba de chi cuadrado para determinar la asociación entre la aparición de un desequilibrio muscular y la de las lesiones. Cuatro atletas (21%) presentaron lesiones en la región de la rodilla. El desequilibrio muscular se asoció con la aparición de lesiones en las tres velocidades probadas (p < 0,05). Se concluyó que un desequilibrio muscular puede estar asociado con la aparición de lesiones en corredores.

Isokinetic performance of knee flexor and extensor muscles in community-dwelling elderly women / Desempenho dos músculos flexores e extensores de joelho de idosas da comunidade no dinamômetro isocinético

AbstractIntroduction The isokinetic dynamometer enables accurate assessment of muscle function. In Brazil, few studies have assessed the isokinetic muscle performance in older adults making interpretation and comparison of results with other studies.Objectives To conduct a descriptive analysis of the performance of the muscle flexor and extensor muscles of the knee joint in elderly community and compare the performance between the age groups 65-74 years and 75 years or more.Methods This is a cross sectional observational study with a convenience sample of 229 elderly community. For the analysis of muscle performance was used isokinetic dynamometer (Biodex System 3 Pro™) in the angular velocities of 60 °/s and 180 °/s. The variables evaluated were peak torque, peak torque normalized by body weight, total work normalized by body mass, total work, average power and agonist/antagonist ratio. Descriptive analysis was used to characterize the sample. For comparison between age groups was used Student's t-test with α = 0.05.Results The elderly women with older age showed a statistically significant decrease in most of the variables (p < 0.05) except for the agonist and antagonist knee (p = 0.398).Conclusions The isokinetic was a sensitive tool to characterize the modifications caused by aging on muscle function. Elderly with results below the lower limits of the confidence intervals for all variables certainly has a decreased strength for the age group evaluated and must be addressed therapeutically. The results can be used as a benchmark in clinical practice and future research.

ResumoIntrodução O dinamômetro isocinético possibilita a avaliação acurada da função muscular. No Brasil, poucos estudos avaliaram o desempenho muscular isocinético em idosos, dificultando a interpretação e comparação dos resultados com outros estudos.Objetivos Realizar uma análise descritiva do desempenho muscular dos músculos flexores e extensores da articulação do joelho de idosas da comunidade e comparar o desempenho entre as faixas etárias de 65 a 74 anos e 75 anos ou mais.Métodos Trata-se de um estudo observacional transversal, com uma amostra de conveniência com 229 idosas da comunidade. Para a análise do desempenho muscular foi utilizado o dinamômetro isocinético (Biodex System 3 Pro®) nas velocidades angulares de 60 °/s e 180 °/s. As variáveis avaliadas foram o pico torque, pico de torque normalizado pela massa corporal, trabalho normalizado pela massa corporal, trabalho total, potência e a relação agonista/antagonista. Foi utilizada análise descritiva para caracterização da amostra. Para comparação entre as faixas etárias foi usado o teste-t de Student considerando α = 0,05.Resultados As idosas com idade mais avançada apresentaram um decréscimo estatisticamente significativo na maioria das variáveis analisadas (p < 0,05) com exceção da relação agonista e antagonista do joelho (p = 0,398).Conclusão O dinamômetro isocinético foi um instrumento sensível para caracterizar as modificações ocasionadas pelo envelhecimento na função muscular. Idosas com resultados abaixo dos limites inferiores dos intervalos de confiança para as variáveis pesquisadas apresentam uma força diminuída para a faixa etária avaliada e devem ser abordadas terapeuticamente. Os resultados podem ser utilizados como parâmetro de comparação na prática clínica e em futuras pesquisas.

Shoulder isokinetic profile of male handball players of the Brazilian National Team

BACKGROUND: Data obtained on an isokinetic dynamometer are useful to characterize muscle status and have been reported in muscle imbalance studies in different types of sport. However, few studies have assessed elite handball players to establish reference values. OBJECTIVE: The purpose of this study was to compare, for the dominant (D) and non-dominant (ND) side, the isokinetic profile of shoulder rotator muscle strength between male handball players (H) and asymptomatic non-athletes (NA). METHOD: Isokinetic concentric and eccentric strength tests for D upper limbs were performed by the H group (n=20) and the NA group (n=12). Internal and external rotator muscle peak torque in concentric action was assessed at 60°/s and 300°/s and in eccentric action at 300°/s. We also calculated conventional balance (the ratio of external rotator peak torque to internal rotator peak torque in concentric action) and functional balance (the ratio of external rotator peak torque in eccentric action to internal rotator peak torque in concentric action). RESULTS: In the H group, dominant limbs were stronger in concentric action for external rotation at 60 and 300°/s. The conventional balance ratio for the D side was significantly lower at 60 and 300°/s for H compared to NA. The functional ratio for the D side was significantly lower at 300º/s for H compared to NA. CONCLUSIONS: Compared to asymptomatic non-athletes, handball players presented significant muscular imbalance resulting from daily sports practice, a known risk factor for shoulder injuries. .

What is the most effective protocol to induce fatiguein knee joint muscles? a systematic review

The aim of this study was to review the literature to see how the protocols are designed to induce kneejoint muscles fatigue using an isokinetic dynamometer. Materials and Methods: This study consisted of asystematic review and the search for the theoretical composition was performed in the PubMed databaseusing as descriptors the words muscle fatigue, knee, and isokinetic, and as filters the words Abstract available,Humans, Randomized Controlled Trial, and English language. It was not set limits for year of publications.Results: twenty nine studies were found, from which, seventeen were excluded due to exclusion criteria.Conclusion: It became evident in the present review that the greatest reduction in the peak torque occurs inprotocols that use series of trials without determining the number of repetitions, requiring that the movementbe executed until attaining exhaustion. However, if there is a need to determine a number of repetitionsto decrease the the knee joint torque to the levels close to the one attained in the exhaustion protocol, theprotocol that most reduced the knee joint flexor and extensor torque was the one that used five series of 30repetitions with interval of one minute between series, independent of the angular speed and the type ofcontraction, concentric or excentric.

Relação entre torque extensor e relação I: Q com salto unipodal triplo horizontal em jogadores profissionais de futebol / Relationship between extensor torque and H: Q ratio with triple hop distance in professional soccer players

OBJETIVOS: 1) Determinar e comparar o torque extensor, relação I:Q e distância do salto triplo entre os membros; 2) identificar a relação entre o torque extensor e relação I:Q com o desempenho no salto triplo em jogadores profissionais de futebol. MATERIAIS E MÉTODOS: Foram selecionados 21 indivíduos, homens, idade média de 23,2 anos (± 3,6), saudáveis, sem histórico de lesões, praticantes profissionais de futebol. Os atletas foram avaliados em um dinamômetro isocinético nas velocidades de 60, 180 e 300°/s, das quais foram obtidos os picos de torque e calculada a relação I:Q nas três velocidades. Foi realizada também a avaliação funcional por meio do salto unipodal triplo horizontal, e desse foi obtida a distância saltada em metros. RESULTADOS: Não houve diferença entre membros (dominante e não dominante) para os testes (p = 0,23). Além disso, foi observada baixa correlação entre o torque extensor e teste funcional nas três velocidades (membro dominante: 60°/s_r = 0,38; 180°/s_r = 0,43*; 300°/s_r = 0,26. Membro não dominante: 60°/s_r = 0,36; 180°/s_r = 0,30; 300°/s_r = 0,48*) (*p < 0,05), assim como na relação I:Q e teste funcional (membro dominante: 60_r = 0,01; 180_r = 0,11; 300_r = - 0,02. Membro não dominante: 60_r = - 0,20; 180_r = - 0,15; 300_r = - 0,18). CONCLUSÃO: Devido à baixa correlação, não é possível substituir a avaliação isocinética pelo salto unipodal triplo horizontal (teste funcional) na avaliação da condição muscular.

OBJECTIVE: The aims of this study were: 1) to determine and compare the extensor torque, H:Q ratio and triple hop distance in functional test between lower extremities; 2) to identify the relationship between extensor torque and H:Q ratio with the performance in triple hop distance in professional soccer players. MATERIALS AND METHODS: Twenty-one healthy male professional soccer players, average 23.2 (± 3.6) years old, without history of injury were selected. The athletes were assessed in an isokinetic dynamometer at three angular velocities: 60, 180 and 300°/s, and from this assessment the peak of torque and calculated H:Q ratio at the three velocities were obtained. The triple hop distance was also used to calculate the hopped distance in meters. RESULTS: No significant difference was found between the lower extremities (dominant and non-dominant) (p = 0.23). Also, a weak relationship between extensor torque and functional test at the three velocities was observed (Dominant: 60°/s_r = 0.38; 180°/s_r = 0.43*; 300°/s_r = 0.26. Non dominant: 60°/s_r = 0.36; 180°/s_r = 0.30; 300°/s_r = 0.48*) (*p < 0.05). Similar results were found for H:Q ratio (Dominant: 60_r = 0.01; 180_r = 0.11; 300_r = - 0.02. Non-dominant: 60_r = - 0.20; 180_r = - 0.15; 300_r = - 0.18). CONCLUSION: Due to a weak relationship, the isokinetic test cannot be replaced by the triple hop distance (functional test) for muscular function assessment.

Resistência ao movimento e atividade eletromiográfica dos músculos flexores e extensores de cotovelo em pacientes hemiparéticos espásticos submetidos à crioterapia e estimulação elétrica neuromuscular / Resistance to movement and electromyographic activity of the elbow flexor and extensor muscles in spastic hemiparetic patients following cryotherapy and electrical stimulation

A espasticidade quase sempre coexiste a um Acidente Vascular Encefálico (AVE), devido à lesão do motoneurônio superior, provocando um impacto nas atividades da vida diária e na qualidade de vida dos pacientes. Por esse motivo é de suma importância o controle do tônus muscular, que pode ser alcançado por meio de recursos fisioterapêuticos, como a crioterapia e a Estimulação Elétrica Neuromuscular (EENM). Como demonstrado em diversas pesquisas na área, esses recursos são vantajosos pelos efeitos fisiológicos que proporcionam, porém, são insuficientes os trabalhos científicos que forneçam embasamento para o tratamento da espasticidade dos membros superiores e, evidenciem o tempo de duração dos efeitos fisiológicos após aplicação desses recursos. Nesse sentido, o presente trabalho vem contribuir para o estabelecimento de protocolo de aplicação de crioterapia e EENM em indivíduos portadores de hemiparesia espástica e, informar a duração dos efeitos após submissão às terapias, por meio da análise da resistência ao movimento dos músculos flexores e extensores de cotovelo antes, depois, 10, 20 e 30 minutos após a aplicação de crioterapia e EENM. Participaram do estudo 15 pacientes com diagnóstico de AVE e diagnóstico fisioterapêutico de hemiparesia espástica, de ambos os sexos, com idade média de 56 ± 16 anos. A avaliação foi realizada antes e após a terapia, e nos instantes de 10, 20 e 30 minutos após o término de sua aplicação, e consistiu na captação da atividade eletromiográfica por meio da Eletromiografia (EMG) de superfície e da resistência ao movimento por meio do Dinamômetro Isocinético, no modo passivo nas velocidades angulares de 30 º/s e 150 º/s. Embora não estatisticamente significativos (p < 0,05) os resultados evidenciam uma redução da resistência à movimentação passiva dos flexores e extensores de cotovelo após a aplicação de crioterapia e EENM, comprovando a eficácia dos recursos fisioterapêuticos na redução da resistência à movimentação passiva de indivíduos hemiparéticos espásticos, embora, apresentem efeitos diferentes com relação ao tempo.

Spasticity often coexists with stroke due to an upper motor neuron lesion, which impacts the patient's quality of life. Therefore, the control of muscle tone through physical therapy such as cryotherapy and Neuromuscular Electrical Stimulation (NMES) is extremely important. Several studies have demonstrated their advantageous physiological effects. However, these studies have not provided sufficient scientific proof for the treatment of upper limb spasticity and the duration of the physiological effects after the therapy. Therefore, this work helps to establish an application protocol for cryotherapy and NMES in individuals with spastic hemiparesis. The resistance to movement of the elbow flexor and extensor muscles before and after application of cryotherapy and NMES was used to determine the effect of the therapies. The study included 15 stroke patients that required physical therapy for spastic hemiparesis. They included both sexes, mean age of 56 ± 16. An evaluation was performed before and after therapy, as well as 10, 20, and 30 minutes following the application, by means of surface electromyography (EMG). The resistance to movement was measured with an Isokinetic Dynamometer in the passive mode at an angular velocity of 30 and 150 º/s. Although not statistically significant (p < 0.05), the results showed a reduced resistance to passive movement of the elbow flexors and extensors after cryotherapy and NMES, allowing us to conclude that physical therapy effectively reduces the resistance to passive movement in spastic hemiparetic patients, however, they have different effects with respect to time.

Application of isokinetic dynamometer in treatment of knee joint contracture by static progressive stretch / 医用生物力学

Objective To report the method used to treat knee joint contracture by static progressive stretch and evaluate its curative effect. Methods Sixteen patients with knee joint contracture after the orthopedic surgery were selected，including 2 femoral shaft fractures, 5 distal femur fracturs, 4 patellar fractures, 5 tibial plateau fractures. The average course of postoperative treatment was 13.7 weeks. Static progressive stretch (SPS) was applied by isokinetic dynamometer, with 5 sets of stretch in one direction for one treatment, each set lasts 5 minutes with 1 minute interval for rest, and the degree of joint position was increased progressively for the next set. Patients received SPS 2 times per day, 30 minutes per time, 5 days per week, and the course of treatment lasted 2 months. The knee flexion degree (F), extension degree (E) and range of motion (R) were measured by goniometer before treatment, after treatment, 6 months after treatment, respectively. Results E, F and R of the knee joint were improved significantly both after treatment and 6 months after treatment as compared with those before treatment. Conclusions Application of isokinetic dynamometer by static progressive stretch can be used to treat knee joint contracture effectively.

Efeito da simulação do jogo de basquetebol sobre o pico de torque e razão funcional dos músculos estabilizadores do tornozelo / Effect of basketball match simulation on peak torque and functional torque ratio of stabilizing muscle of the ankle

O presente estudo teve por objetivo analisar o efeito de simulação do jogo de basquetebol sobre o pico de torque (PT) dos músculos eversores e inversores do tornozelo e a razão de torque funcional eversor excêntrico/inversor concêntrico (EVEEXC/INVCON). Dez basquetebolistas universitários saudáveis, sem instabilidades mecânicas ou funcionais no tornozelo realizaram uma simulação do jogo de basquetebol a partir de um teste laboratorial. O teste foi composto por uma sucessão de esforços físicos intensos e breves distribuídos igualmente em quatro períodos de 10 minutos cada, considerando demandas mecânicas e fisiológicas de um jogo de basquetebol. Previamente ao início do teste (Avaliação 1) e após o 2º (Avaliação 2) e o 4º (Avaliação 3) período, foram realizadas cinco contrações isocinéticas máximas concêntricas e excêntricas dos grupos musculares eversores e inversores do tornozelo, separados por dois minutos de intervalo, nas velocidades de 60º/s e 120°/s. Após a verificação da normalidade de distribuição dos dados com o teste Shapiro-Wilk, utilizou-se o teste ANOVA medidas repetidas e o teste post-hoc de Bonferroni para a comparação das variáveis entre as avaliações. Adotou-se p < 0.05. Não houve diferença significativa para a razão EVEEXC/INVCON entre as avaliações realizadas. Entretanto, verificou-se declínio do PT EVEEXC a 60º/s e 120º/s para a Avaliação 1 quando comparada à Avaliação 2. Para o PT INVCON observou-se redução dos valores em relação à Avaliação 1, quando comparados à Avaliação 2 e à Avaliação 3 a 60º/s e à Avaliação 3 a 120º/s. Diante destes resultados, conclui-se que o progresso da simulação do jogo de basquetebol promove redução do PT dos músculos eversores e inversores do tornozelo.

The aim of this study was to analyze the effect of Basketball match work simulation on peak torque (PT) of ankle evertor and invertor muscles and on eccentric evertor/concentric invertor torque ratio (EVEECC/INVCON). Ten healthy college basketball players, without mechanics or functional ankle instability performed a laboratory-based protocol representative of work rates observed during basketball match-play. The test was composed of a succession of intermittent physical effort equally distributed in four periods of 10 minutes each, considering the mechanical and physiological demands of a basketball match-play. Prior to the start of the trial (Evaluation 1) and after 2° (Evaluation 2) and 4° (Evaluation 3) period, the subjects performed five maximal isokinetic concentric and eccentric contractions of ankle invertors and evertors muscles, separated by two minutes rest, at 60 °/s and 120 °/s. After testing for normality of data distribution with the Shapiro-Wilk test, was used the ANOVA repeated measures and post-hoc Bonferroni test for comparison of variables between assessments. Was adopted p < 0.05. There was no significant difference for EVEECC/INVCON torque ratio between assessments. However, there was a decrease in PT EVEECC at 60º/s and 120º/s for the Evaluation 2 when compared to Evaluation 1. There was a reduction of PT INVCON values in relation to Evaluation 1, compared to Evaluation 2 and to Evaluation 3 at 60°/s and to Evaluation 3 at 120°/s. Given these results, we conclude that the progress of simulation basketball match-play lead a reduction on PT of the ankle evertors and invertors muscles.

Efeito agudo de diferentes formas de aquecimento sobre a força muscular / Acute effect of different forms of heating on muscle strength

Os exercícios físicos têm a finalidade de manter e melhorar um ou mais componentes do condicionamentofísico, dentre os quais está a força muscular. Para o aperfeiçoamento do treino da força são utilizadas váriastécnicas de aquecimento, com vistas a alcançar seus benefícios. O objetivo deste estudo foi avaliar a forçamuscular dos extensores do joelho, antes e após a aplicação de alongamento estático (GAE), exercício aeróbico (GEA) e associação de ambos (GAE+GEA), verificando, dessa maneira, os efeitos dos diferentes tiposde aquecimento sobre a força muscular. Para tanto, participaram do estudo 16 indivíduos do sexo feminino(idade de 22,5 ± 4,7 anos e IMC de 20,8 ± 1,83 kg/m2), divididos em três grupos (GAE, GEA e GAE+GEA).As variáveis observadas foram: pico de torque concêntrico, pico de torque excêntrico e trabalho total. Cada grupo, posteriormente à avaliação da força no dinamômetro isocinético, realizou, após um intervalo mínimode 48 horas, um protocolo de aquecimento seguido da reavaliação da força muscular. Os resultadosobtidos indicaram não haver influência significativa inter e/ou intraprotocolos nas variáveis observadas,considerando nível de significância de p ≤ 0,05. Portanto, conclui-se que, de forma aguda, o desempenho deforça muscular na extensão do joelho não sofreu alterações significativas após os diferentes protocolos deaquecimento utilizados.

Avaliação isocinética dos músculos extensores e flexores de joelho em jogadores de futebol profissional / Isokinetic evaluation of knee extensor and flexor muscles

INTRODUÇÃO E OBJETIVOS: Estudos que relacionam parâmetros de desempenho muscular em diferentes esportes, e, especialmente no futebol, têm sido frequentemente reportados na literatura. Entretanto, as variações metodológicas entre os diversos estudos, o tipo de dinamômetro usado em cada pesquisa e o posicionamento dos sujeitos durante as avaliações resultam na divergência dos dados coletados. Portanto, o objetivo deste estudo foi realizar uma coleta de dados que forneçam valores sobre o perfil muscular e estabelecer parâmetros normativos relativos ao desempenho muscular de jogadores profissionais de futebol, fundamentando a pesquisa científica e estudos futuros. MÉTODOS: A amostra consistiu de 39 atletas pertencentes a um clube de futebol de elite da capital gaúcha. Para avaliação do desempenho muscular foi utilizado um dinamômetro isocinético e os testes consistiram de contrações concêntricas máximas, sendo testados os músculos extensores e flexores do joelho nas velocidades 60º/s e 240º/s. Realizou-se a análise das médias através do teste t (amostras independentes) para investigar diferenças bilaterais nos parâmetros avaliados. Para todos os procedimentos estatísticos, o intervalo de confiança foi de 95 por cento (p < 0,05). RESULTADOS: Os resultados deste estudo caracterizaram o perfil muscular de jogadores profissionais do futebol relativo à capacidade de produção de torque, trabalho e potência máxima, normalizados pelo peso corporal. Além disso, foram observadas diferenças significativas entre pernas em algumas variáveis. CONCLUSÃO: Os dados normativos estabelecidos podem ser utilizados como valores de referência na prevenção, treinamento e reabilitação dos atletas, além de servirem de referência para futuros estudos que tenham como objetivo relacionar os parâmetros de desempenho muscular à incidência de lesões no futebol.

INTRODUCTION AND OBJECTIVE: Studies that relate parameters of muscular performance in different sports, and especially in soccer, have been frequently reported in the literature. However, the methodological variations among studies, the type of dynamometer used in each search and placement of each subject during the evaluations results in the divergence of the data collected. Therefore, the objective of this study was to perform a data collection to provide figures on the muscular profile and establish normative parameters for the professional soccer players' muscular performance, supporting scientific research and future studies. METHODS: The sample consisted of 39 athletes from a professional soccer club in Porto Alegre. In order to evaluate muscular performance, an isokinetic dynamometer was used and the tests consisted of maximal concentric contractions, being knee flexors and extensors muscles tested at 60º/s and 240º/s velocities. Analysis of means by t test (independent samples) was used to investigate significant differences between legs considering the parameters evaluated in this study. For all statistical procedures the confidence interval was 95 percent (p <0.05). RESULTS: The results of this study characterized the muscular profile of professional soccer players on the capacity of torque, work and maximum power, normalized by body weight. Moreover, significant differences were observed between legs considering some of the study's variables. CONCLUSION: The normative data set can be used as reference values for prevention, training and rehabilitation of athletes, and serve as reference for future studies with the aim to relate parameters of muscular performance and incidence of injuries in soccer.

Measurement of Proprioception of the Knee in Hemiplegic Patients Using an Isokinetic Dynamometer

OBJECTIVE: To measure knee joint proprioception quantitatively in hemiplegic patients after brain injury using an isokinetic dynamometer. METHOD: Thirty healthy subjects and 24 hemiplegic patients participated in this study. Joint position sense was evaluated with passive angle reproduction of 30degrees and 60degrees of knee flexion and kinesthesia was evaluated with the threshold for detection of passive movementfrom 45degrees of knee flexion. We used toe-"up or down"-test for conventional clinical method. RESULTS: Significant proprioceptive deficit was observed not only in paretic knees of both right and left hemiplegic patients (p0.05). CONCLUSION: The quantitative test using an isokinetic dynamometer is a reliable method to measure knee proprioception, and it is possible to detect proprioceptive deficit in hemiplegic patients. Conventional clinical assessments are poor for predicting the results of the quantitative measure in the nonparetic knee. This quantitative method may be useful in diagnosis and follow-up of knee proprioception of hemiplegic patients after brain injury.

Effects of Muscle Fatigue on Shoulder Proprioception

OBJECTIVE: To investigate the changes of shoulder proprioception in normal subjects, according to the direction of the evoked fatigue on the shoulder muscle group. METHOD: 20 healthy volunteers (14 males and 6 females, age 20~35 years) with entirely normal shoulders participated in this study. Before fatigue exercises, the proprioception tests were performed during active reposition (ARP) and passive reposition (PRP) of dominant shoulder, using isokinetic dynamometer, System 3 Pro (Biodex medical system, New York, USA). Three trials each of active and passive repositioning (2degrees/sec) were recorded. We also estimated the results of the peak torque shoulder movements. The subjects performed maximal efforts with five repetitions on the direction of flexion, abduction, internal rotation and external rotation. The mean values of maximal concentric voluntary contraction (MVC: peak torque of each muscle group contraction) were recorded. We repeated fatigue exercises until the peak torque dropped to 30% three times consistently, then retested the proprioception of shoulder joints. We compared the proprioceptive changes of the shoulder with pre-fatigue test and post-fatigue test on the direction of shoulder movements. RESULTS: There were significant differences of shoulder proprioception between pre-fatigue test and post-fatigue test of ARP in shoulder abduction and external rotation (p<0.05). CONCLUSION: In our study, the proprioception of shoulder joint decreased more prominently on external rotation and abduction movements under severely provoked muscle fatigue around the shoulder joint.

A Quantitative Assessment of Knee Extensor Spasticity Using Isokinetic Dynamometer

OBJECTIVE: To find useful parameters in biomechanical assessment of spasticity. METHOD: Knee extensor muscles of 60 limbs of 47 patients which showed clinical spasticity were stretched by isokinetic dynamometer. Stretch was done with the velocities of 60o/sec, 120o/sec, 180o/sec, 240o/sec. Four parameters [torque onset angle (TOA), peak torque angle (PTA), peak eccentric torque (PET), peak eccentric torque area (PETA)] were measured at each stretch velocity. Then, regression analysis was performed in relationship between each parameter and strech velocity. We analysed the correlation between the slope of each parameter in regression equation and clinical Modified Ashworth Scale (MAS) RESULTS: The slope of TOA and PTA had negative value so that they showed the decreasing trend of their value according to increasing velocity. On the other hand the slope of PET and PETA had positive value which meant that those parameters increased according to increasing velocity. The slope of PET and PETA were correlated statistically. The higher the MAS score was, the larger value of slope of PET, PTEA were noted. CONCLUSION: Peak eccentric torque and Peak eccentric torque area are thought to be useful parameters in biomecha nical assessment of spasticity.

Comparison of Isokinetic Strength of Knee and Pulmonary Function between Collegians and Hockey Players in College

OBJECTIVE: The purpose of this study was to examine the strength of the knee and pulmonary function comparing collegians and hockey players in college. METHOD: KINdegreeCOM isokinetic dynamometer and medigraph were used to evaluate strength of the right lower extremity and pulmonary function to 30 male students comprising 15 hockey players and 15 collegians with no significant difference in age, weight, and height between the two groups. All subjects used their right lower limb as dominant limb. RESULTS: 1) The significant differences between collegians and hockey players were found in the peak torque at 60o/sec,180o/sec. 2) The siginficant differences between collegians and hockey players were found in forced vital capacity, forced expiratory volume in one second and expiratory reserve volume on the pulmonary function. 3) The significant correlation between isokinetic strength and pulmonary function were found in peak torque. CONCLUSION: It is turned out that hockey players in college have much better isokinetic strength and pulmonary function than collegians, so it is suggested this result have to be considered in selecting hockey players and exercise prescription.

Analysis of Torque Curve in Isokinetic Knee Dynamometer

OBJECTIVE: To analyze the patterns of isokinetic knee torque curves in normal population and determine the characteristics of those curves. METHOD: Two hundred and eightly-six normal subjects were included. The isokinetic knee torque curves were divided into three parts; to the angle of peak torque generation, to the point 10~20 degrees prior to end of joint motion, and to the end of joint motion. Each part was classified as convex(1), flat(2) and concave(3) type according to the shape. The curves were named such as 1-2-2 in order. Types of the curves, peak torque, angle of knee at peak torque, total acceleration energy, age, and sex of the subjects were compared. RESULTS: For knee extensors, frequencies of the curve types were 1-2-2(A), 1-2-1(B), 1-3-1(C), and 1-3-2(D). Mean ages of type A and B curves were slightly higher than types of C and D. Mean peak torque was greatest in type D. For knee flexors, the frequencies were 1-2-2(A), 1-2-1(B), and 1-1-2(C). Female predominance were found in type B while type C was found mostly in male. Mean peak torque was greatest in type C. CONCLUSION: The most common torque curve type was 1-2-2 for knee extensors and flexors. Torque curve types of knee extensors showed differences in age and torque curve types of knee flexors showed differences in sexual distribution.

Isoknetic Dynamometric Technique for the Quantitative Assessment of Spasticity / 中国康复理论与实践

@# Spasticity is a common problem in upper motor neuron lesions.Assessment of spasticity is extremely valuable in quantifying the effects of a therapeutic intervention.But it is,in other hand,a difficult and challenging problem.Objective:The present study was undertaken to determine the feasibility of quantifying spasticity by the pendulum test using the isokinetic dynamometric technique.We suggest that this machine can be used to perform pendulum test to quantify spasticity.Method:We studied the lower limb muscle tone in 34 spastic subjects,and in 9 flaccid paralysis control subjects,and 10 normal control subjects.Result:Typical pendulun test goniograms of each group were obtained and 5 parameters are extracted from the goniograms to evaluate the degree of spasticity. They are:Al(the flexion angle of the first drop)、R1(relaxation index)、R2(amplitude ratio)、T(time of swings)、F(frequency of swings).The correlation coefficients are calculated to determine the reliability of the parameters(>0.90 for three consecutive test;>0.80 for different days).The validity is determined by t test(p<0.01).Conclusion:The method of using isokinetic dynamometric technique combining pendulum test to quantify spasticity is a reliable,valid,accurate and convenient method of assessing spasticity.

A Quantitative Assessment of Spasticity in Hemiplegic Patients Using Isokinetic Dynamometer

OBJECTIVES: The biomechanical assessment of spasticity has been developed recently, but not standardized yet for the test procedures and parameters of measurement. This study was designed for the development of standardized method of the biomechanical assessment of spasticity using the isokinetic dynamometer. METHOD: The plantar flexor muscles of both ankles were stretched from 40o plantar flexion to 20o dorsiflexion using the isokinetic dynamometer at the angular velocities of 15o, 30o, 60o, 90o, 120o, 180o, and 300o per second. Three parameters, peak eccentric torque(PET), torque threshold angle(TTA), and angle at peak torque(PTA) were analysed. RESULTS: PET increased and TTA decreased significantly in the involved side. The side to side difference of PET and TTA increased in the patient group with more spasticity. The side to side difference of PET increased, but the side to side difference of TTA decreased with the increase in the angular velocity. CONCLUSIONS: The isokinetic dynamometer is useful in the assessment of the spasticity of ankle plantar flexor of hemiplegic patients. PET and TTA are useful parameters. The faster angular velocities seemed to be more appropriate for the analysis of torque values and the slower angular velocities seemed to be more appropriate for the analysis of thresholds.

The Quantitative Assessment of Ankle Plantar Flexor Muscle Tone

OBJECTIVE: We designed this study to evaluate muscle tone by using a biomechanical method and to provide data for the future studies about muscle tone. METHOD: We evaluated 29 subjects without known neuromuscalar diseases using the biomechanical method. Both plantar flexors of each subject were passively stretched by isokinetic dynamometer from 30degrees plantar flexion position to 10degrees dorsiflexion position. Peak eccentric torque (PET) and torque threshold angle (TTA) were calculated at angular velocity of 10degrees/sec, 90degrees/sec and 300degrees/sec. Regression lines from torque/position curve at 10degrees/sec and 300degrees/sec were considered an intrinsic stiffness index (ISI) and total stiffness index (TSI). Stretch reflex threshold speed (SRTS) was defined as the minimum speed of plantar flexion movement in which EMG reflex activity in plantar flexor muscles is induced. RESULTS: The mean of TTA was higher in 10o/sec than in 300degrees/sec. The means of ISI and TSI were 0.11+/-0.08, and 0.18+/-0.04. The mean of SRTS was 125.2+/-48.3degrees. No statistical difference in each parameter was found according to the side or gender. CONCLUSION: ISI, TSI, PET, TTA and SRTS using a biomechanical method are thought to be useful parameters for the quantitative assessment of muscle tone change of ankle plantar flexors.